Treatment of cellulosic textile materials



Patented Aug. 28, 1945 TREATMENT OF CELLULOSIC TEXTILE MATERIALS GeorgeP. Vincent, Briarclitf, N. Y., Archie Louis Dubeau; Rumi'ord, R. I., andJohn Francis Synan, Fall River, Mass., assignors to The Mathieson AlkaliWorks, Inc., New York, N. Y., a corporation of Virginia No Drawing.Application January 23, 1942, Serial No. 427,950

' 8 Claims.

This invention relates to the treatment of cellulosic textile materials,such as cotton piece goods, synthetic cellulosic fibers, mixtures ofcotton and rayon in woven form and yarns of both natural and syntheticcellulosic material.

Hypochloritcs have heretofore been used extensively in the bleaching ofcotton fibers and synthetic cellulose fibers. The use of hypochlorites,such as sodium or calcium hypochlorites in bleaching such fibrousmaterial is accompanied by the tendency to form oxycellulose. Thisdegradation product is objectionable in yarns or cloth 'as it causestendering of the fiber, the development of yellow color on storage anduneven dyeing. Fairly good result may be obtained. however, and theamount of oxycellulose formed may be kept to a minimum by carefulchemical control of the process. It is, however, generally impossible tocomplete y prevent the formation of oxycellulose.

It has recently been found that vastly improved results can be obtainedand all danger of formation of oxycellulose can be avoided by bleachingthe goods with sodium chlorite in an acid solution. The hypochloritesused in bleaching are in an alkaline solution. Sodium chlorite destroysthe coloring matter in the material being bleached but is not powerfulenough toattack the fibers themselves. Careful control is therefore notnecessary and better and more permanent whites are obtained without lossof tensile strength even when a high brightness is desired. Wherethe-facilities are available for the use of acid solutions, bleachedgood of a high quality can thus be produced at a low cost by the use ofsodium chlorite but the process requires radical changes in bleachingmethods in plants that have heretofore employed sodiiun or calciumhypochlorite bleaching processes using alkaline solutions.

In'the copending application Serial No. 405,989 filed August 8,1941,'one of us has disclosed a process of bleaching cellulose textilematerials by using a mixture of sodium chlorite and a hypochlorite in analkaline solution. In the process disclosed in that application the materials to be bleached are scoured prior to the bleaching operation. Thepresent application is directed to a modification of the processdisclosed in that copending application which is applicable totreatment, for instance in a package machine, of material that has hadno previous scouring.

In theconventional package machine process the operation consists ofboth a bleaching and scouring action carried on simultaneously at auniformly high -temperature. In accordance with the present'inventionthe material is packed in the package machine and a bleach liquor,comprising an alkaline aqueous solution of a chlorite anda hypochloriteand to vfiiich a suitable detergent has been added, is circulatedthrough it under pressure at a moderate temperatur such as indicated inthe above-noted application. After the bleaching operation has beencompleted the temperature is raised to approximately 00 F. at whichtemperature a scouring action takes place due to the syntheticdetergent. At the end of the scouring operation the chloritehypochloritedetergent solution is run of! and the material washed with hot water.

In conducting the bleaching and scouring of cellulosic textile materialsin a package machine using a mixture of sodium chlorite and ahypochlorite in an alkaline solution, in conjunction with a suitabledetergent in accordance with the present invention, we have found thatsuperior results may be obtained over those which have heretofore been"obtained by employing a hypo chlorite alone as the bleaching agent. Theprac-- tice results in good color, decrease of oxycellulose and may becarried out with a smaller amount of available chlorine than when ahypochlorite is employed as the only bleaching agent.

As stated, the process is carried out in an alkaline solution, and whilethe pH of the solution may vary within wide limits we find that the bestresults are obtained if the pH is maintained between 8.0 and 11.0. Thegrams per liter of available chlorine present in the solution may alsovary within wide limits, but we have found that the best results areobtained when the grams per liter of available chlorine are between 1.0and 10.0. Any of the well known detergents may be employed for thescouring operation. We preferably employ one of a number of well knownsynthetic detergents including a large number of sulfated or sulfonatedorganic compounds. Among the detergents which we may use are:

Sodium sulfoethyl methyl oleyl amide (sold under the trade name ofIgepon T) Sodium borosult'ate of octadecenyl alcohol '(sold under thetrade name of Mapromine) Sodium lauryl sulfate (sold under the tradename of Gardinol) Sodium sulfate of octadecenyl alcohol (sold under thetrade name of Modinol) Sodium sulfonate of alkylated phenol (sold underthe trade name of Nacconal) Sodium sulfonate of alkylated benzene (soldunder the trade. name of Santomerse) Sodium diamyl to sodium dioctyl,sulfosuccinate (sold under the trade name of Aerosol) IAS stated, theprocess is conducted by placing cellulosic textile materials which havehad no previous scourin in a package machine and then circulating thebleach liquor under pressure. We preferably prepare a solutioncontaining the selected detergent, sodium chlorite and a relatively weakalkali, such as tetra sodium pyrophosphate. This liquid is circulatedthrough the machine for a period of about 5 minutes at a temperaturefrom 85 to 95 F. to wet the cellulosic material being treated. Thedesired amount of a hypochlorite, such assodium hypochlorite, is thenadded in solution and circulated for a period of approximately 45minutes. During this time the temperature is raised to a temperature of110 to 120 F. Steam is then turned on and the solution circulated forapproximately 45 minutes. During this last step the temperature israised to approximately 200 F. in the first or minutes and held at thattemperature until the end of the run. Y

As specific examples of the process the following are cited:

Example I A solution containing approximately 2 parts of Igepon T, 6parts of sodium chlorite and 24 parts of tetra sodium pyrophosphate wascirculated through a machine containing yam to be treated solutioncirculated for about 45 minutes. During this period of time thetemperature was increased to 122 F. The available chlorine presentduring this portion of the process was suflicient to carry out thenecessary bleaching operation At that time the temperature was raised byturning on steam and in 15 to 20 minutes was brought up to 200 F. Thetemperature of 200 F. was maintained for a period of approximatelyminutes during which time there was no available chlorine present andthe securin operation was performed by the detergent. The results ofthis test were the production of good color and removal of motes.Theresulting absorbency was good, and the strength tested by thecupro-ammonium viscosity test was excellent,

Example II In this instance a very coarse and cheap yarn was scoured andbleached by placing the yarn in the package machine and then treating itwith a solution containing 1% parts of Igepon T, 4 parts-ofsodiumvchlorite and 19 parts of tetra sodium pyrophosphate for a periodof approximately 5 minutes at a temperature of approximately 95 F. towet out the yarn. 9 parts of available chlorine as sodium hypochloritewere then added and the composite solution circulated for 45 minutes. Atthis point. thesteam was turned on and the temperature increased to 200F. after about 20 to 25 minutes and held there to the end of the run.The circulation was continued for about 45 minutes after the steam wasturned on. The treated material was then washed with water at 120 F. andagain at 150 F. The solution was tested for available chlorine which wasfound to be present in desired quantities until the temperature reached120 F, after which the available chlorine decreased until there was noneavailable when a temperature of 180 F. was reached. The results of thisprocedure were ,the production of good color, fairly good mote removal,excellent strength and excellent dyein quality. The strength wasmeasured by the cupro-ammonium viscosity method.

Example III In this instance the material treated was yarn andsubstantially the same procedure was followed. The original solutionconsisted of 2 parts of Igepon T, 4 /2 parts of sodium chlorite and 24parts of tetra sodium pyrophosphate. After the initial wetting, 92 partsof a 10% solution of hypochlorite were added and after circulating thecomposite solution for a period of substantially 45 minutes thetemperature was raised to 200 F. and the process continued for anadditional 45 minutes. The results obtained were substantially the sameas those set forth in the preceding tests.

\ Example IV In this instance the same procedure was followed, theinitial solution comprising Mapromine ,1 part, sodium chlorite 4.15parts, and tetra sodium pyrophosphate 6 parts. After the material waswet with this solution, a solution of sodium hypochlorite containing 8parts of available chlorine was added and the process continued asheretofore described.

In the examples given, the ratio of hypochlorite to sodium chlorite issubstantially l /zzl on the basis of available chlorine but the ratiomay be varied within certain limits. As stated, the process results inthe production of material equal to or better than that obtained bytreatment with a hypochlorite alone with the use of less avail ablechlorine in the bleaching solution.

While the examples given disclose. the use of sodium hypochlorite, otherhypochlorites used in bleaching, such as calcium hypochlorite, may beemployed. Likewise chlorites of the other alkali metals may be used inplace of sodium chlorite. The temperatures employed during the bleachingoperation of the process and the higher temperature employed during thescouring portion of the process are not, critical. It is preferable tohave the solution slightly heated during the initial portion of theprocess as setforth in the examples, but the temperature may be 'lowerthan 85 F. or higher than 95 F. It is necessary that an elevatedtemperature be employed during the scouring portion of the process andany temperature slightly below the boiling point of water may be used.

We claim:

1. The process of bleaching and scouring cellulosic textile materialwhich comprises treating the material with an alkaline solution of ahypochlorite, an alkali metal chlorite and a detergent at a moderatetemperature not substantially exceeding about 120 F., for a period oftime sufilcient to bleach the textile and substantially to exhaust thehypochlorite present in the solution, then raising the temperature ofthe solution to substantially 200 F. and continuing the treatment for aperiod of time sufiicient for scouring the textile.

2. The process of bleaching and scouring cellulosic textile materialwhich comprises treating the material with an alkaline solution of ahypochlorite, an alkali metal chlorite and a detergent at a temperatureof about F. to F. for a period of time sufficient to bleach the textileand substantially to exhaust hypochlorite present in the solution, thenraising the temperature of the solution to substantially 200 F. andcontinuing the treatment for a period of time sufficient for scouringthe textile.

3. The process of bleaching and scouring cellulosic textile materialwhich comprises treating the material with an alkaline solution of ahypochlorite, sodium chlorite and a" detergent at a moderate temperaturenot substantially exceeding about 120 F;, for a period of timesufiicient to bleach the textile and substantially to exhaust thehypochlorite present in the solution, then raising the temperature tosubstantially 200 F. and continuing the treatment for a period of timesuflicient for scouring the textile.

4. The process of bleaching and scouring cellulosic textile materialwhich comprises treating the material with an alkaline solution of ahypochlorite and sodium chlorite in a ratio of substantially one andone-half to one based on the available chlorine, and a detergent at amoderate temperature not substantially exceeding about 120 F. for aperiod of time sufllcient to bleach the textile and substantially toexhaust the hypochlorite present in the solution, then raising thetemperature-t the solution to substantially 200 F. and continuing thetreatment for a period of time suflicient for scouring the textile.

5. The process of bleaching and scouring cellulosic textile materialwhich comprises treating the material with a solution of a hypochlorite,an alkali metal chlorite and a'detergent having a pH of from 8 to 11 ata moderate temperature not substantially exceeding about 120 F. for aperiod of time suificient to bleach the textile and substantially toexhaust the hypochlorite present in the solution, then raising thetemperature of the solution to substantially 200 F. and continuing thetreatment for a period of time sufiicient for scouring the textile.

6. The process of bleaching and scouring cellulosic textile materialwhich comprises treating the material with an alkaline solution of ahypofor scouring the textile.

chlorite, sodium chlorite and sodium sulfoethyl methyl oleyl amide at amoderate temperature not substantially exceeding about F., for a. periodof time suilicient to bleach the textile and substantially to exhaustthe hypochlorite, present in the solution, then raising the temperatureof the solution to substantially 200 F. and continuing the treatment fora period of time suificient for scouring the textile.

7. The process of bleaching and securing cellulosic textile materialwhich comprises treating the material with an alkaline solution of ahypochlorite, sodium chlorite and sodium borosulfate of octadecenylalcohol at a moderate temperature not substantially exceeding (about 120F. for a period of time suilicient to bleach the textile and'substantially to exhaust the hypochlorite present in the solution, thenraising the temperature of the solution to substantially 200 F. andcontinuing the treatment for a period of time sufficient 8. The processof bleaching and scouring ce1-. lulosic textile material which comprisestreating the material with an alkaline solution of a hypochlorite,sodium chlorite and a detergent at a moderate temperature notsubstantially exceeding 120 F., for a period of time sufficient tobleach the textile and substantially to exhaust the hypochlorite presentin the solution, the solution having a pH 01' from 8 to 11 andcontaining from 1 to 10 grams per liter of available chloriney the ratioof hypochlorite to chlorite in the solution being substantially one andone-half to one on the basis of available chlorine, then raising thetemperature of the solution to substantially 200 F., and continuing thetreatment for a period 01' time suificient for scouring the textile.

GEORGE P. VINCENT. ARCHIE LOUIS DUBEAU. JOHN FRANCIS SYNAN.

